Mercury 75 Hp 1987-90

Hello,
wanted to ask for help in this little situation with our boat.. it acts like it loses it prime or something. we have had it to the shop, had the carbs syn, and linked. had everything adjusted. but it is still acting like its losing its prime. we have replaced the bulb and the lines to the carbs. re-checked the diaphram and everything. but nothing has changed. we took the buld loose from the fuel line, and connected a small electric fuel pump.. it runs a little bit longer , but the crazy thing about it the electric fuel pump.. we let it run for a sec or two, and cut it off at the battery, start the boat and it runs a bit longer than with the bulb, how can this work without the pump on... and why would it work better with the pump than with the bulb??? we do not know what else to do with this motor.. and help would be greatly appreciated... thank you for your time... Ray

Use only a Mercury/Quicksilver bulb. The cheaper ones aren't known for being good out of the box. Check the fuel pickup inside the tank for cracks/leaks.

Rebuild your fuel pump. Be sure to get the Mercury kit as it contains new type check valves. I can send you a copy of the TSB if you PM me your email addy.

I typed in the wrong year fro my murcury 75 hp.. I received a message from a fellow crappie fisherman, and he stated that the year of my motor is not a 1987-1990.... It is a 1984 model...which i am glad to know that, for parts issues.... still haven't figured it all out yet.... we have replaced the hoses, we disconnected the hose from the tank and put it in a plastic gas can to see if it would make a difference.. it did not... We have not rebuilt the pump yet... is there anything else that it can be ,before we rebuild the pump??? thanks for all of your help and we greatly appreciate everything....

Ray

Just rebuild the pump...its very easy...and is likely full of debris.

TMD

Thanks for your replies. I think that i will rebuild the pump.. as I was looking on the ILL.chart for my pump parts, I see a few things that I didn't see in my pump... whats up with that??????